Overview of Intel 8086 Microprocessor Video Lecture - Computer Science Engineering (CSE)

this presentation is an introduction to
8086 microprocessor main features of a
zero eight six microprocessor it is a
16-bit microprocessor eight zero eight
six has a 20-bit address bus and it can
access up to two to the power 20 memory
locations that is 1 MB it can support up
to 64 K IO port it provides 14 16-bit
registers word size is 16-bit and double
word size is 4 bytes
it has multiplexed address and data bus
from ad 0 to 80 15 and a 16 to a 19 it
has two operating modes Max and min it 0
8 6 consists of 2 units
execution unit and bus interface unit
execution unit it performs the
arithmetic and logical operations
required for any program it consists of
arithmetic logic unit ALU performs the
arithmetic and logical operations
required of any program general-purpose
registers set of registers that can be
addressed either as a bit or 16-bit
execution unit consists of stack pointer
base pointer index registers Flags
instruction decoder and timing and
control unit bus interface unit it
handles all the transfer of data and
address on the buses segment registers
used to address memory space address
compute engine converts the logical
address that is held by the segment
register into a physical address
internal memory holds the instruction q
BAU prefetches 6 instructions for the
you to use it's a technique called
pipelining flag register flag register
contains information reflecting the
current status of a microprocessor it
also contains information which controls
the operation of the microprocessor here
we have stated the control and status
flags of 8086 microprocessor segmented
memory there are four segment registers
in a zero eight six
as you can see we have code segments
used for storing instructions data
segments an extra segment used for
storing data bytes and stack segment
used as a stack and to store the return
address 8 0 8 6 has 1 MB memory space
here we assume that code segment points
to 1 2 3 4 H to calculate the physical
address of the start of code segment 1 2
3 4 H is translated into 1 2 3 4 0 H by
the address compute engine the
instruction pointer in this case is 0 5
6 7 8 H which is then added to code
segment value to get the final code
segment value as 1 7 9 b8 H this is the
pen diagram of 8086 8086 is a 40 pin IC
packet there are two modes of operation
minimum mode and maximum mode in minimum
mode we have a single processor system
all control signals for i/o or memory
are generated on its own in max mode
additional CRO processors can be
connected it's used for complex or large
operations the level of pin minimum or
maximum decides the operating mode when
24 to 31 issues two different sets of
signals one for each mode the eight
addressing modes in 8 0 8 6
microprocessor are immediate addressing
registered addressing direct addressing
register indirect addressing based
addressing indexed addressing based
indexed addressing based indexed with
displacement addressing comparison
between 8 0 8 5 in 8 0 8 6 8 0 8 5 is 8
bit processor with 16 bit address bus
and access up to 64 KB memory whereas 8
0 8 6 is 16 bit processor has 20 bit
address bus and can access up to 1 MB of
memory 8 0 8 6 supports pipelining and
multi processing but 8 0 8 5 does not
support these 8 0 8 5 can address 2 to
the power 8
input/output and eight zero eight six
can access two to the power 16
input/output it zero eight five only
supports integer and decimal
whereas eight zero eight six supports
integer decimal and ask I arithmetic it
0 8 5 does not support multiplication
and division whereas eight zero eight
six supports eight zero eight five
supports only single operating mode
whereas eight zero eight six operates in
two modes in eight zero eight five
memory space is not segmented but in
eight zero eight six memory space is
segmented this video lecture was
presented by students of NIT hum input
Department of electronics and
communication engineering thank you